A system and method for improving the linkage and security of records is provided. Generally, the present invention can be viewed as providing methods for selecting an ideal identifier, from a series of test identifiers, for linking more than one associated record. In this regard, one embodiment of such a method, among others, can be broadly summarized by the following steps: accessing several parameters for each test identifier; determining if an error rate of the test identifier is an improved error rate over an error rate of an existing identifier; determining if the test identifier reduces linkage error; and selecting the test identifier as the ideal identifier if the test identifier has a lower overall error rate, as determined by the steps of determining if an error rate of the test identifier is an improved error rate over an error rate of an existing identifier and determining if the test identifier reduces linkage error, compared to other test identifiers.